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user19161
11:13 AM
@robjohn You're up early.
 
κρανίοπεριπολία
κρανίοπεριπολία
>8(
 
user19161
@κρανίοπεριπολία What does that smiley mean?
 
κρανίοπεριπολία
κρανίοπεριπολία
That's my impersonation of the "mean square."
 
Dominic Michaelis
Dominic Michaelis
huhu you all
 
κρανίοπεριπολία
κρανίοπεριπολία
hihi to you to
 
Deele
Deele
11:23 AM
Hey, how to calculate in excel a number, that I can substract 5% and
 
κρανίοπεριπολία
κρανίοπεριπολία
:D
 
Deele
Deele
get specific number
 
robjohn
robjohn
@JasperLoy I am?
 
Deele
Deele
like, I need to get 250, and I have found that 263,16-(263,16*0,05) = 250,002
 
κρανίοπεριπολία
κρανίοπεριπολία
We are going to see a lot of new users around here soon:
 
Deele
Deele
11:27 AM
how to "reverse" this expression?
 
κρανίοπεριπολία
κρανίοπεριπολία
Why exactly are there so many "First Posts" right now? I've never seen more than 3, and now there are 88. - 7h ago by Andrew Salmon ▼
 
user19161
@DominicMichaelis That guy just edited his question.
 
Dominic Michaelis
Dominic Michaelis
how i love that
i will prove that when f is convex a local minimum implies a global minimum
 
user19161
@DominicMichaelis Haha, just see my elementary proof!
 
Dominic Michaelis
Dominic Michaelis
@jasper yeah but i don'T want to copy you ;)
so i make it as complicated as possible
 
user19161
11:32 AM
@DominicMichaelis Yeah, it's good to see different solutions, though in this case, I doubt the asker will understand, but it's still instructive for other readers.
 
Dominic Michaelis
Dominic Michaelis
i am eating right now, it will take some time ^^
 
user19161
@DominicMichaelis Only 3 votes for my answer, I thought it would have 9000 by now!
 
Dominic Michaelis
Dominic Michaelis
yeah i love how easy you made it, bad luck you was faster as i ^^
 
user19161
I hope it gets 9000 later!
 
user19161
I only know easy proofs, I am only a banana.
 
Dominic Michaelis
Dominic Michaelis
11:37 AM
the most votes on an answer I saw was over 3000
 
Deele
Deele
How to find a number, that substracted by 5%, equals given number?
 
Dominic Michaelis
Dominic Michaelis
@deele 0.95 x= given number
 
Deele
Deele
@DominicMichaelis No, that is not solution. For example, given number is 2500, and solution (according to goal seeker in excel) is 2631,578..., and if I substract 5% from 2631,578 I get 2500
@DominicMichaelis but if I reverse that, it is solution, 2500 / 0,95 = 2631,578...
 
Dominic Michaelis
Dominic Michaelis
wait wait wait i always see the same number
the problem is that $(0.95 * x)*(1.05)\neq x
 
user19161
11:52 AM
I just answered a beautiful question!
 
κρανίοπεριπολία
κρανίοπεριπολία
by a beautiful mind
 
awllower
awllower
what beautiful question?
 
user19161
3
Q: Finding the triples

user69872If $x,y,z$ are integers satisfy $xyz+4(x+y+z)=2(xy+yz+zx)+7$ .How to find the triples$(x,y,z)$ that satisfy the equation

algebra-precalculus
 
Dominic Michaelis
Dominic Michaelis
@jasper i updated mine answer
 
awllower
awllower
I see.
It is indeed beautiful!
 
Dominic Michaelis
Dominic Michaelis
11:57 AM
gee that got a long answer, i hope someone will read it although it is so long
 
awllower
awllower
BTW, in English it is a "convex" function, not "konvex".
 
Dominic Michaelis
Dominic Michaelis
oh crap
 
awllower
awllower
minor point. :D
 
Dominic Michaelis
Dominic Michaelis
most times i called it convex ^^
 
user19161
It shows he is German. =)))
 
awllower
awllower
12:04 PM
:)
 
Dominic Michaelis
Dominic Michaelis
I guess i should at a picture to the definition of convexity
 
user19161
I thought the beautiful question will have 9000 votes by now...
 
awllower
awllower
It resembles a result in calculus of variations, stating that, if F is convex, and if u^k minimizes an integral function related to F, then u^k minimizes that functional in the whole Lipschitz space!
 
user19161
Dinner time...
 
awllower
awllower
Bye! Blue banana
 
Dominic Michaelis
Dominic Michaelis
12:07 PM
bye
mh maybe it would be better if i only prove the simple case where $f$ is 2 times differentiable
 
awllower
awllower
But the most interesting, or troublesome, case is when there is no such condition!
:D
 
Dominic Michaelis
Dominic Michaelis
yeah i just use the convexity without being differentiable a single time
 
awllower
awllower
Good!
Hm... Yesterday I sleeped only 5 hours, so I think I am going to take a rest now!
later everyone!
 
Dominic Michaelis
Dominic Michaelis
well i used when f is 2 times differentialbe and f'' > 0 that f is convex, as I didn't want to write down the proof for the convexity
seee you later
 
awllower
awllower
:-D
 
user19161
12:46 PM
@awllower The past tense of sleep is slept.
 
user19161
1:12 PM
Guys, I just posted my 400th answer, yay!!!
 
anorton
anorton
That's awesome!
 
Tobias Kildetoft
Tobias Kildetoft
@JasperLoy cool.
I just noticed I have exactly 100 answers
 
anorton
anorton
I have 116. Now I have to answer 34 more so it's a nice multiple of 50. :\
 
Zignd
Zignd
Hey guys, can you give me some help?

I'm solving some exercises for school about complex numbers and it asks this:

If f(z) = z2 - z + 1, then f(1 - i) is equal to:
a) i

b) -i + 1

c) i - 1

d) i + 1

e) -i

My answer:
f(1 - i) = ( 1 - i ) * 2 - ( 1 - i ) + 1
f(1 - i) = 2 - 2i - 1 + i +1
f(1 - i) = 2 - i

Of course this answer is not an option, but it's written below the question that the answer is the letter C, how can that be possible? What I did wrong?.
 
Tobias Kildetoft
Tobias Kildetoft
1:28 PM
@Zignd is the z2 a $z^2$?
 
Zignd
Zignd
no it's z * 2
 
Tobias Kildetoft
Tobias Kildetoft
what an odd way of writing it then
 
Zignd
Zignd
do you think my answer is correct?
 
user67848
user67848
Well, then f(z)=z+1
 
Tobias Kildetoft
Tobias Kildetoft
also, if it was a square then that would explain why you get a result that is not an option
since you calculation is correct
 
user67848
user67848
1:30 PM
If it is z^2, I get -i
 
Zignd
Zignd
@user67848 Well I saw an commentary below this question that says that "the answer for this question is the letter E (-i) instead of C" I think it was incorrectly written (the question).
 
user67848
user67848
@Zignd Did the worksheet have f(z)=z2-z+1, with the 2 after the z? In this case, I think they just messed up the exponent.
 
Zignd
Zignd
@user67848 Yeah you're probably right. Thanks for helping guys. Cya.
 
user67848
user67848
@Zignd Btw, an easy way to get -i is to manipulate the expression z^2-z+1=z^2-2z+1+z=(z-1)^2+z.
 
user19161
40 more to cap today.
 
Tobias Kildetoft
Tobias Kildetoft
1:45 PM
I think I have only capped once
 
user68578
user68578
2:28 PM
So jealous of how good people on here are!
 
Jorge Fernández
Jorge Fernández
2:39 PM
hi guys
 
hhh
hhh
3:04 PM
Simple q about matlab, how to read the output?

solve(x==y+1, y^2==z,z==9)

ans =

x: [2x1 sym]
y: [2x1 sym]
z: [2x1 sym]
 
Charlie
Charlie
@κρανίοπεριπολία Hi!
@karl's hii!
 
Karl's students
Karl's students
@Charlie hi honey!
 
Charlie
Charlie
@Karl'sstudents how are you sweetheart?
 
Karl's students
Karl's students
@Charlie I am fine, and I miss Jasper Loy!
 
Charlie
Charlie
@Karl'sstudents I saw him yesterday
 
Karl's students
Karl's students
3:18 PM
@Charlie I am solving a mathematics problem now...
 
Charlie
Charlie
@Karl'sstudents ah, wonderful!
@Jasper Hi, Jaspy, we miss you :)
 
Karl's students
Karl's students
@Charlie I am hibernating...
 
Charlie
Charlie
@Karl'sstudents Oh!
 
Karl's students
Karl's students
3:31 PM
There is an interview in LaTeX site. The interviewee is a TeX expert from China. chat.stackexchange.com/rooms/1728/textalk-interviews
 
Charlie
Charlie
3:45 PM
:)
 
Arkamis
Arkamis
morning
 
Charlie
Charlie
4:01 PM
@Arkamis Hi Ed!
 
Arkamis
Arkamis
@Charlie How goes it?
 
Charlie
Charlie
everything fine, and you?
 
Arkamis
Arkamis
sore
Played my last hockey game of the season last night
 
Charlie
Charlie
Oh noes! Did you win?
 
Arkamis
Arkamis
Nope, lost 2-1, was a good game
 
Dominic Michaelis
Dominic Michaelis
4:05 PM
huhu
 
Charlie
Charlie
@DominicMichaelis hi Dommy
@Arkamis hahaha
 
Arkamis
Arkamis
Sore though, I got knocked on my ass pretty hard, feet kicked out from under me, landed right on my tailbone.
 
Charlie
Charlie
Ouch!!!
A game where no one gets hurt, is not a good game
 
Dominic Michaelis
Dominic Michaelis
there is no laurent series tag?
 
Arkamis
Arkamis
@charlie This is true.
 
Dominic Michaelis
Dominic Michaelis
4:18 PM
shall i make one ?
 
Arkamis
Arkamis
@DominicMichaelis Check meta first, see if there's been any discussion. Otherwise, go ahead. Seems like a reasonable tag.
 
Dominic Michaelis
Dominic Michaelis
search for laurent gives 0 results
 
Arkamis
Arkamis
fire away
 
Charlie
Charlie
Bang bang
 
Dominic Michaelis
Dominic Michaelis
is there in the tag body no mathe allowed?
 
Arkamis
Arkamis
4:25 PM
@DominicMichaelis Correct
from what I remember
 
Dominic Michaelis
Dominic Michaelis
explain a laurent series without using integrals formula, thats a hard one for tabu ...
 
Charlie
Charlie
Nice I changed my gravatar :)
 
Dominic Michaelis
Dominic Michaelis
i will search for some questions which should have that tag
you have the word wunderbar ? :D
 
Charlie
Charlie
4:43 PM
No hahaha
 
Jayesh Badwaik
Jayesh Badwaik
@DominicMichaelis is it like awesomebar?
 
Dominic Michaelis
Dominic Michaelis
i guess it is pretty much the same as awesome
 
Charlie
Charlie
Wunderkind
 
Dominic Michaelis
Dominic Michaelis
4:56 PM
gee there are a lot of questions about laurent series
 
Arkamis
Arkamis
@DominicMichaelis Don't go too edit-happy
People will not want to see a flood of older Laurent Series questions on the front page ;)
 
Dominic Michaelis
Dominic Michaelis
oh so i will make it from time to time
 
Charlie
Charlie
@κρανίοπεριπολία hi Skull!!!
 
κρανίοπεριπολία
κρανίοπεριπολία
@Charlie Chucky? Is that you?
 
Charlie
Charlie
@κρανίοπεριπολία yipyipyip
 
κρανίοπεριπολία
κρανίοπεριπολία
5:02 PM
 
Charlie
Charlie
:)
@κρανίοπεριπολία how are you ?
 
κρανίοπεριπολία
κρανίοπεριπολία
@Charlie Fine thanks. How are you?
 
Charlie
Charlie
@κρανίοπεριπολία I'm good, Skull
 
κρανίοπεριπολία
κρανίοπεριπολία
@Charlie Rating please.
 
Charlie
Charlie
@κρανίοπεριπολία 7.83
 
κρανίοπεριπολία
κρανίοπεριπολία
5:13 PM
@Charlie Fair enough.
 
Charlie
Charlie
@κρανίοπεριπολία really?
 
κρανίοπεριπολία
κρανίοπεριπολία
@Charlie yipyipyip
 
Charlie
Charlie
@κρανίοπεριπολία :D
 
κρανίοπεριπολία
κρανίοπεριπολία
@Charlie Not everything the Jacksons do is a 9.
IMO
 
Charlie
Charlie
@κρανίοπεριπολία agreed
 
κρανίοπεριπολία
κρανίοπεριπολία
5:19 PM
@Charlie Nice gravatar Chucky!
 
Charlie
Charlie
@κρανίοπεριπολία Thanks, you liked?
 
κρανίοπεριπολία
κρανίοπεριπολία
@Charlie Oh yeah...eyes without a face...black cat
Very nice.
 
Charlie
Charlie
@κρανίοπεριπολία :D
@κρανίοπεριπολία ;)
 
κρανίοπεριπολία
κρανίοπεριπολία
@Charlie };)
 
Charlie
Charlie
@κρανίοπεριπολία O:-)
 
κρανίοπεριπολία
κρανίοπεριπολία
5:29 PM
>8(
 
Charlie
Charlie
:*
 
κρανίοπεριπολία
κρανίοπεριπολία
:*
 
Charlie
Charlie
@κρανίοπεριπολία what did you remove?
 
κρανίοπεριπολία
κρανίοπεριπολία
:-O
this^
 
Charlie
Charlie
Aah
 
κρανίοπεριπολία
κρανίοπεριπολία
5:34 PM
@Charlie Is that OK?
 
Charlie
Charlie
@κρανίοπεριπολία yipyipyip
 
κρανίοπεριπολία
κρανίοπεριπολία
$(Good)^\infty$
 
Charlie
Charlie
:)
 
κρανίοπεριπολία
κρανίοπεριπολία
Our gravatars^^ contrast each other nicely :)
 
Charlie
Charlie
Like black and silver:)
 
κρανίοπεριπολία
κρανίοπεριπολία
5:41 PM
$\Huge\text{Bleed the Silver & Black}$
Silver & Black Is What I Bleed
 
Charlie
Charlie
@κρανίοπεριπολία a lot of f***, no?
 
κρανίοπεριπολία
κρανίοπεριπολία
@Charlie Yeah, too much.
 
Charlie
Charlie
:-/
 
anon
anon
 
WhitAngl
WhitAngl
Hi! Does anyone know PavelM ? He used to be on math.SE (at least until January)...
 
Peter Tamaroff
Peter Tamaroff
5:57 PM
@anon Sup, nerdizzle?
 
anon
anon
yo, P-drizzle
 
Jayesh Badwaik
Jayesh Badwaik
shizzle shizzle
 
Peter Tamaroff
Peter Tamaroff
@anon The commutator subgroup is the smallest normal subgroup of $G$ such that $G/N$ is abelian! =)
 
anon
anon
reading alex I see
 
Tobias Kildetoft
Tobias Kildetoft
I wonder who found this to be a good question math.stackexchange.com/questions/344917/…
 
anon
anon
6:10 PM
ouch
 
Peter Tamaroff
Peter Tamaroff
@anon Ah?
 
Peter Tamaroff
Peter Tamaroff
6:24 PM
 
κρανίοπεριπολία
κρανίοπεριπολία
Does anybody experience this drop down message in chat?

There seems to be a problem connecting to the server.
Please check your internet connection and reload this page.
 
Arkamis
Arkamis
@WhitAngl PavelM left
He changed his user name to 5pm at some point; there is a meta thread on his departure.
 
Peter Tamaroff
Peter Tamaroff
@κρανίοπεριπολία That happens to me when I close the browser on my phone and reopen it, say.
 
WhitAngl
WhitAngl
@Arkamis: thanks! Do you know his real name by any chance ?
 
Arkamis
Arkamis
@WhitAngl cannot say I do
But others around do
 
WhitAngl
WhitAngl
6:37 PM
ok ; I'd like to acknowledge him in a paper, and referring to a pseudonym that doesn't even exist anymore doesn't do him justice ;)
 
Arkamis
Arkamis
24
Q: What happened to 5PM?

maximumtagHey I am wondering where 5PM is? I enjoyed reading his posts on partial differential equations and am just curious. The account seems to be deleted.

discussion specific-user
 
WhitAngl
WhitAngl
yep I just saw. I'm reading the thread. I didn't know PavelM=5pm
thanks!
 
Peter Tamaroff
Peter Tamaroff
7:00 PM
@AlexanderGruber Yello.
 
Alexander Gruber
Alexander Gruber
@PeterTamaroff hi
 
Peter Tamaroff
Peter Tamaroff
@AlexanderGruber I'm showing any finite domain is a division ring.
I'm thinking as follows:
 
Alexander Gruber
Alexander Gruber
fun :)
 
Peter Tamaroff
Peter Tamaroff
Take $R=\{r_0,r_1,r_2,\dots,r_m\}$ where $r_0=0\neq 1 =r_1$.
Choose a $r_j\neq 1,0$ and make $r_jR=\{r_0,r_j,\dots,r_\ell\}$
Since $r_j\neq 0,1$, there must exist an $r_i$ in $r_jR$ with $r_i=1$ (since $r_jR=R$) so $1=r_jr_i$ for some $i$.
Then repeat till exhaustion of elements of $R$.
Obviosuly this is just a sketch. And I need to look at right products too, not left only.
 
Tobias Kildetoft
Tobias Kildetoft
@PeterTamaroff note that the inverse of some non-zero element will actually be a power of that element
 
Alexander Gruber
Alexander Gruber
7:09 PM
where do you use the domain property?
 
anon
anon
the domain property is needed to know that multiplication-by-r_j is injective (and hence 1 has a preimage under it, r_i)
showing finite division rings are necessarily commutative is much harder
 
Alexander Gruber
Alexander Gruber
yes, that works then
pigeonhole principle stuff
haha, wonder who nuked our answers @anon?
 
Tobias Kildetoft
Tobias Kildetoft
it's the same reason it is enough to check closed under composition to check whether something is a subgroup of a finite group (inverses then being automatic)
 
Peter Tamaroff
Peter Tamaroff
@AlexanderGruber @anon was downvoted!
 
anon
anon
we both were
 
Jayesh Badwaik
Jayesh Badwaik
7:20 PM
sounds like someone has some fetishes about his reputation points
 
κρανίοπεριπολία
κρανίοπεριπολία
fetish?
 
Carpediem
Carpediem
 
Peter Tamaroff
Peter Tamaroff
@anon True. Was it caveman?
 
anon
anon
fetishes plural?
I don't care to jump to conclusions, nor do I care who it is.
 
Jayesh Badwaik
Jayesh Badwaik
yeah, can be more than one... who knows
 
WhitAngl
WhitAngl
7:22 PM
just got 20+ historical french math books for free today.. from Weil, Banach, Bourbaki, Serre, Dieudonné, Fréchet... :) :) cool!
 
anon
anon
nice
 
κρανίοπεριπολία
κρανίοπεριπολία
That is cool.
Especially Bourbaki.
 
Alexander Gruber
Alexander Gruber
@κρανίοπεριπολία my thoughts exactly
 
WhitAngl
WhitAngl
"Algèbre" and "Intégration" :)
 
Carpediem
Carpediem
@WhitAngl Dieudonne ?? mdr
 
Peter Tamaroff
Peter Tamaroff
7:29 PM
@WhitAngl Damn! Lucky!
 
Carpediem
Carpediem
@WhitAngl je faisais reference a l'humoriste polémique bien entendu
 
WhitAngl
WhitAngl
Cartan-Dieudonné theorem... ;)
I like book give-aways at Harvard :p
 
Alexander Gruber
Alexander Gruber
do you live in the harvard area?
 
WhitAngl
WhitAngl
yep
 
Carpediem
Carpediem
@WhitAngl where did you get them exactly from ?
 
κρανίοπεριπολία
κρανίοπεριπολία
7:33 PM
@WhitAngl Your libraries are the largest in the world.
 
WhitAngl
WhitAngl
@Carpediem 33 oxford street, in the SEAS department. But it was only until 2pm. I don't know whether they plan to renew the event
(in Maxwell Dworkin)
 
Carpediem
Carpediem
0
Q: Derivatives of functions defined implicitly

CarpediemLet $F$ be a real-valued function of two real variables and assume that the partial derivatives $D_1 F$ and $D_2 F$ are never zero. Let u be another real-valued function of two real variables such that the partial derivatives $\partial u/ \partial x$ and $\partial u/ \partial y$ are related by th...

partial-derivative
 
user19161
Why did I get a few votes from the -1 times -1 question today? It was not bumped.
 
Dominic Michaelis
Dominic Michaelis
no idea
 
user19161
Hmm, maybe something new was linked to it then...
 
user19161
7:38 PM
Ah, I have 100 votes for that answer, so a Great Answer Badge.
 
Dominic Michaelis
Dominic Michaelis
congratulation
and i need 41 reputation to cap today ^^
 
user19161
Also, I have capped for the day, thank you for your support, ladies and gentlemen.
 
Carpediem
Carpediem
Can someone help me with the above problem ?
 
Peter Tamaroff
Peter Tamaroff
@TobiasKildetoft Oh, I think that is tidier. I just multiply an element by itself till I get $1$.
 
Alexander Gruber
Alexander Gruber
i don't have a great answer badge :(
 
user19161
7:43 PM
@AlexanderGruber That is because you are already great!
 
user19161
Only bananas like me need badges.
 
Alexander Gruber
Alexander Gruber
i suppose that's true
 
user19161
You people will win Fields medals in future.
 
Alexander Gruber
Alexander Gruber
that's a lot like a great answer badge
 
user19161
Nah, the badges mean nothing.
 
user19161
7:45 PM
Only love is real.
 
Tobias Kildetoft
Tobias Kildetoft
@PeterTamaroff right, you just need to argue why you get 1 at some point
 
Peter Tamaroff
Peter Tamaroff
@TobiasKildetoft Sure. Though my idea also works.
 
user19161
I am trying to figure out which post was linked to the -1 times -1 question, hmm...
 
user19161
@amwhy With 40k, you can now retire!
 
amWhy
amWhy
@JasperLoy One point shy 39999...and capped in terms of up-votes for the day :-)
So I'll either hope for an "accept" before the day ends, or wait it out for the new day ;-)
 
user19161
7:49 PM
Everyone, happy Good Friday.
 
user19161
I am not Christian, but Jesus was still a great man, no less.
 
Peter Tamaroff
Peter Tamaroff
@anon Suppose that $R$ is a finite domain and I showed for each $r\neq 0$ there exists $r'\in R$ such that $rr'=1$.
 
user19161
Strange things happen. I was expecting votes for my latest answers, but I got votes for my -1 times -1 answer instead. Life is strange...
 
Carpediem
Carpediem
@JasperLoy It's not friday yet
 
Peter Tamaroff
Peter Tamaroff
Does this suffice to show invertibility?
 
Dominic Michaelis
Dominic Michaelis
7:53 PM
how to make a floor in LaTeX ?
 
user19161
@Carpediem Commenting on your own question with "can someone help me" will not help you get answers faster. In fact, it might have the opposite effect...
 
Alexander Gruber
Alexander Gruber
what is good friday?
 
user19161
@AlexanderGruber It is the day Jesus died on the cross.
 
Alexander Gruber
Alexander Gruber
@JasperLoy huh. that's... a little counterintuitive.
 
user19161
He said "God, why hast thou forsaken me?"
 
Carpediem
Carpediem
7:55 PM
@JasperLoy Meh..
 
user19161
And then he said "It is finished!"
 
user19161
To Christians, Jesus died for our sins and salvation.
 
user19161
Because of his death, Christians have life.
 
Alexander Gruber
Alexander Gruber
oh, that's right.
@DominicMichaelis lfoor rfloor
 
Peter Tamaroff
Peter Tamaroff
@JasperLoy The funny thing is the "sacrifice"
 
user19161
7:57 PM
@PeterTamaroff Well, I was just presenting the Christian point of view objectively.
 
Peter Tamaroff
Peter Tamaroff
Hey, you're gonna die and free people from sins. But then you'll be reborn, and be immortal and overlord of the world.
 
user19161
Of course, I have a Buddhist point of view myself.
 
Peter Tamaroff
Peter Tamaroff
What kind of "sacrifice" is that?
It was a total win win situation!
 
user19161
And to Muslims, Jesus is a prophet of God, but not God himself.
 
user19161
And to historians, there is no doubt about Jesus's existence on earth.
 
Carpediem
Carpediem
7:59 PM
@PeterTamaroff Can I ask you a question about a problem from Apostol
 
Alexander Gruber
Alexander Gruber
@JasperLoy is that true?
 
user19161
@AlexanderGruber Well, maybe there is some doubt, but not much!
 
Dominic Michaelis
Dominic Michaelis
oh i found one for this one here
 
Peter Tamaroff
Peter Tamaroff
@Carpediem OK.
@anon I got it.
 
Carpediem
Carpediem
@PeterTamaroff It's problem 8 page 303 (Section 9.8)
 
Peter Tamaroff
Peter Tamaroff
8:01 PM
@Carpediem Let me go fetch the book.
 
Carpediem
Carpediem
@PeterTamaroff It's volume 2
 
user19161
I wonder why so many questions have no accepts.
 
Peter Tamaroff
Peter Tamaroff
@Carpediem Ugh, I don't have that one in paper, let me look it up in the PC.
 
user19161
Is it because the asker does not really understand the solutions?
 
user19161
If so, they should really comment to ask for clarification.
 
Peter Tamaroff
Peter Tamaroff
8:04 PM
@Carpediem It's about showing properties of closed sets?
Oh,no wait,
 
Carpediem
Carpediem
Euh no
Here is the subject
1
Q: Derivatives of functions defined implicitly

CarpediemLet $F$ be a real-valued function of two real variables and assume that the partial derivatives $D_1 F$ and $D_2 F$ are never zero. Let u be another real-valued function of two real variables such that the partial derivatives $\partial u/ \partial x$ and $\partial u/ \partial y$ are related by th...

partial-derivative
 
Peter Tamaroff
Peter Tamaroff
@Carpediem Oh, I really don't know about that.
I will study it this semester though.
 
Carpediem
Carpediem
@PeterTamaroff OK thanks anyway
 
Alexander Gruber
Alexander Gruber
@Carpediem try adding some tags
 
user19161
So guys, I plan to have 1k each month for the next 9 months. That will bring me to 30k this year.
 
Peter Tamaroff
Peter Tamaroff
8:08 PM
@JasperLoy That's not impossible.
I am however baffled by how Brian gets 8-9k each month, on average.
 
user19161
@PeterTamaroff Of course, I never speak of impossible things...
 
user19161
There can be miracles when you believe.
 
user19161
@PeterTamaroff Well, he has many accepts and also many fans.
 
user19161
I think @amwhy can get 100k this year if you continue at the same rate...
 
Dominic Michaelis
Dominic Michaelis
@jasper i plan to get mh i don't know i never plan something
 
user19161
8:15 PM
@DominicMichaelis What is mh?
 
Dominic Michaelis
Dominic Michaelis
just a sound when someone is thinking
 
user19161
lol
 
user19161
But it's really good practice writing solutions here. Will prepare you for writing books.
 
Alexander Gruber
Alexander Gruber
i use too much rep on bounties
 
user19161
I think I won't go to the other chat rooms from now, just stay in this one.
 
user19161
8:22 PM
Hey @argon happy Good Friday!
 
Argon
Argon
@JasperLoy To you too! :)
 
Dominic Michaelis
Dominic Michaelis
mh i got 8,2 k reputation in 43 days
i guess i will reach 20 k this year
 
Peter Tamaroff
Peter Tamaroff
I'm wearing a matching t-shirt for the occasion @JasperLoy
Let me show you.
 
user19161
@PeterTamaroff I wanna see your face!
 
user19161
Still waiting...
 
user19161
8:28 PM
Oh noes, I think Pedro has been kidnapped!
 
Peter Tamaroff
Peter Tamaroff
 
user19161
@PeterTamaroff Where is your face?
 
Peter Tamaroff
Peter Tamaroff
@JasperLoy Up! Heheheheh
I took it before you made that request...
 
user19161
@PeterTamaroff That is more important!
 
user19161
Anyway the T-shirt is very suitable.
 
Dominic Michaelis
Dominic Michaelis
8:32 PM
@peter do you think the hint is enough or should i make it explicit ?
 
Peter Tamaroff
Peter Tamaroff
@DominicMichaelis Maybe you can wait for the OPs input.
 
robjohn
robjohn
I am amazed that this answer hasn't gotten a comment for being so huge.
 
Peter Tamaroff
Peter Tamaroff
@robjohn What the...?!
 
Dominic Michaelis
Dominic Michaelis
at first i wanted to wrote "the obvious choice" but i thought it would be to chatty
 
robjohn
robjohn
@PeterTamaroff that is just a small pair of integers... there are many larger ;-)
 
Peter Tamaroff
Peter Tamaroff
8:36 PM
@robjohn I edited it, linked to PasteBin
 
WhitAngl
WhitAngl
still nobody know the identity of 5pm / PavelM ?
 
nerdy
nerdy
Dodek, lets suppose the set of vectors i gave you {(1 0 0 0 ) , (0 1 0 0 ), (2 0 0 0 )} implements the column vectors of a matrix, and that matrix implements Ax=b . I wanna turn the matrix A into reduced row echelon form, do i have 2 degrees of freedom to choose the free variables ?
 
Dominic Michaelis
Dominic Michaelis
argh i freaking hate it when people edit their question to add more questions
 
Peter Tamaroff
Peter Tamaroff
@DominicMichaelis I'm answering that one.
 
Dominic Michaelis
Dominic Michaelis
it's one line
preimages of closed sets are closed
 
robjohn
robjohn
8:48 PM
@PeterTamaroff I like my solution better. No need to move the answer off-site
 
Peter Tamaroff
Peter Tamaroff
@robjohn What was your solution?
 
Dominic Michaelis
Dominic Michaelis
i really thought that this answer would get more upvotes
 
robjohn
robjohn
@PeterTamaroff look
 
Peter Tamaroff
Peter Tamaroff
@robjohn Great one! claps
 
Dominic Michaelis
Dominic Michaelis
why not just taking preimages ?
 
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